Linear actuator

ABSTRACT

A linear actuator is configured to provide the moving force for adjustable furniture, such as beds, chairs, or tables. The linear actuator includes a drive assembly, rigid arm, and linkage assembly. The rigid arm includes a pusher block with one or more attachment projections where the linkage assembly is attached.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/639,307 (“the '307 Application”), filed on Jun. 30, 2017 and entitledLINEAR ACTUATOR, which is a continuation of U.S. patent application Ser.No. 14/445,432 (“the '432 Application”), filed on Jul. 29, 2014,entitled LINEAR ACTUATOR, and issued as U.S. Pat. No. 9,732,832, whichclaims the benefit of U.S. Provisional Application No. 61/862,409 (“the'409 Application”), filed Aug. 5, 2013 and entitled IMPROVED LINEARACTUATOR. The '307 Application, the '432 Application, and the '409Application are all hereby incorporated by this reference in theirentireties.

FIELD OF THE INVENTION

The present disclosure reveals a new design for a linear actuator thatmodifies the positioning in adjustable furniture

BACKGROUND

A linear actuator is an actuator that creates motion in a straight line,in contrast to the circular motion of a conventional electric motor.Linear actuators are widely used within the area of adjustablefurniture, such as beds, chairs, or tables, where they may be used foradjusting the position of adjustable furniture, such as the lifting andreclining of motion chairs, the height of a table, or the position ofthe mattress surface of a bed. The actuator is typically comprised of anelectric motor drive assembly that drives a threaded spindle. Thespindle is retained within a rigid arm, and the electric motor driveassembly is attached to the rigid arm with a plurality of threadedfasteners. A pusher block is threaded onto the spindle and is secured inlinear recesses within the arm. As the electric motor drive assemblyturns the spindle, the pusher block moves from one end of the arm to theother end. The direction of movement is determined by the direction ofthe spindle's rotation.

One end of the prior art actuators may be secured to the adjustablefurniture by a rear mounting bracket. The actuators are also attached tothe furniture by a pair of levers or linkages. One end of the respectivelinkages is secured to the pusher block with a plurality of threadedfasteners. The other end of the respective linkages communicates withthe furniture. Movement of the pusher block moves the linkages andadjusts the position of the furniture.

The prior art linear actuators are costly to manufacture. Connection ofthe electric motor drive assembly to the rigid arm using threadedfasteners is disadvantageous because it is a time-consuming andcomplicated method of assembling the actuators. The prior art actuatorsare also difficult to mount on adjustable furniture. Use of threadedfasteners on the pusher block makes it difficult for assembly lineworkers to align the furniture so that the levers line up with threadedapertures in the pusher block.

Accordingly, there is a need for a linear actuator that can be quicklyassembled and mounted onto adjustable furniture.

SUMMARY

The terms “invention,” “the invention,” “this invention” and “thepresent invention” used in this patent are intended to refer broadly toall of the subject matter of this patent and the patent claims below.Statements containing these terms should be understood not to limit thesubject matter described herein or to limit the meaning or scope of thepatent claims below. Embodiments of the invention covered by this patentare defined by the claims below, not this summary. This summary is ahigh-level overview of various embodiments of the invention andintroduces some of the concepts that are further described in theDetailed Description section below. This summary is not intended toidentify key or essential features of the claimed subject matter, nor isit intended to be used in isolation to determine the scope of theclaimed subject matter. The subject matter should be understood byreference to appropriate portions of the entire specification of thispatent, any or all drawings, and each claim.

The present invention relates to an improved linear actuator. Theimproved linear actuator is designed to provide the moving force foradjustable furniture, such as beds, chairs, or tables. The improvedlinear actuator overcomes problems with the prior art by reducing thenumber of necessary parts and simplifying assembly to save productioncosts.

While the improved linear actuator is directed at use of the actuator inadjustable furniture, the improved linear actuator may be adapted foruse in machine tools and industrial machinery, in computer peripheralssuch as disk drives and printers, in valves and dampers, and in manyother places where linear motion is required.

Various implementations described in the present disclosure can includeadditional systems, methods, features, and advantages, which cannotnecessarily be expressly disclosed herein but will be apparent to one ofordinary skill in the art upon examination of the following detaileddescription and accompanying drawings. It is intended that all suchsystems, methods, features, and advantages be included within thepresent disclosure and protected by the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and components of the following figures are illustrated toemphasize the general principles of the present disclosure.Corresponding features and components throughout the figures can bedesignated by matching reference characters for the sake of consistencyand clarity.

FIG. 1 is a front perspective view of one embodiment of a linearactuator.

FIG. 2 is a perspective view of an alternative embodiment of a linearactuator.

FIG. 3 is a sectional view of the linear actuator of FIG. 2.

FIG. 4 is a side view of the linear actuator of FIG. 1.

FIG. 5 is a perspective view of an alternative embodiment of a linearactuator.

FIG. 6 is a sectional view of the linear actuator of FIG. 5.

FIG. 7 is a rear perspective view of the linear actuator of FIG. 1.

FIG. 8 is an enlarged view of the dis-assembled rigid arm and drivemotor of the linear actuator of FIG. 1.

FIG. 9 is an enlarged view of the dis-assembled rigid arm and holder ofthe linear actuator of FIG. 1.

FIG. 10 is an exploded assembly view of the linear actuator of FIG. 1.

DETAILED DESCRIPTION

The subject matter of embodiments of the present invention is describedhere with specificity to meet statutory requirements, but thisdescription is not necessarily intended to limit the scope of theclaims. The claimed subject matter may be embodied in other ways, mayinclude different elements or steps, and may be used in conjunction withother existing or future technologies. This description should not beinterpreted as implying any particular order or arrangement among orbetween various steps or elements except when the order of individualsteps or arrangement of elements is explicitly described. Directionalreferences such as “up,” “down,” “top,” “left,” “right,” “front,”“back,” and “corners,” among others are intended to refer to theorientation as illustrated and described in the figure (or figures) towhich the components and directions are referencing.

FIGS. 1, 4, and 7 illustrate an embodiment of a linear actuator 16according to the present disclosure. An electric drive motor assembly 2is connected to a rigid arm 3. The rigid arm 3 is formed of stainlesssteel or other suitable material, and also includes a plastic cover 17.A threaded spindle 5 is retained inside the arm. A spindle nut 6 isthreaded onto the spindle 5, and a pusher block 7 is attached to thespindle nut 6. The pusher block 7 straddles the rigid arm 3 and slidesup and down the arm 3 as the electric drive motor assembly 2 turns thespindle 5. A holder 4 is attached to the other end of the rigid arm 3 toretain one end of the spindle 5 and to provide mounting points for theactuator.

The pusher block 7 provides a connection point for communicating forcegenerated by the improved linear actuator 16 to the adjustablefurniture. To simplify assembly of the actuator 16 with adjustablefurniture, the top of the pusher block 7 incorporates a clevis 18.Apertures in the clevis 18 are adapted to receive a clevis pin 19 orother suitable fastener. A single linkage 8 connects the pusher block 7to a torque tube assembly 14. An aperture at the lower end of the singlelinkage 8 is adapted to receive the clevis pin 19. A cotter pin 20 maybe used to secure the clevis pin 19. Use of a clevis pin 19 to attachthe linkage 8 and pusher block 7 eliminates the need for additionalbrackets and threaded fasteners to facilitate the attachment. The pin 19also eliminates the need to mold threaded screw-receiving apertures intothe pusher block 7.

The clevis 18 may also be incorporated onto one or more sides of thepusher block 7 (see FIGS. 2, 3, 5, and 6). FIG. 2 depicts an embodimentof the improved actuator 16 with the clevis 18 incorporated into theside of the pusher block 7. In this embodiment, a clevis pin 19 is usedto secure the linkage 8. FIG. 3 is a cross sectional view of thisembodiment. FIG. 5 depicts an embodiment of the improved actuator 16with the clevis 18 incorporated into the side of the pusher block 7,with a threaded bolt 11 securing the linkage 8. FIG. 6 is a crosssectional view of this embodiment.

FIG. 4 is a side view of the improved actuator 16. The single linkage 8has a unique lever shape that may be adapted to fit specificrequirements for different embodiments of adjustable furniture. A singledual angle bracket 13 is moveably attached to the upper end of thelinkage 8 and may be attached to a torque tube assembly 14 thattransmits the force of the actuator 16 to the adjustable furniture. FIG.7 is a rear view of the improved linear actuator 16. A bolt 12 (see FIG.7) or similar fastener moveably secures the upper end of the singlelinkage 8 to the dual angle bracket 13. Threaded fasteners 15 secure thedual angle bracket to the torque tube assembly 14. The torque tubeassembly 14 communicates with the adjustable furniture (not shown). Aclevis pin 19 secures the lower end of the linkage 8 to the clevis 18 atthe top of the pusher block 7. A cotter pin 20 secures the clevis pin19. The improved linear actuator 16 simplifies the process of attachingthe actuator 16 to the furniture because the clevis 18 makes it easierfor assembly workers to align the furniture, torque tube assembly 14,linkage 8, and pusher block 7. Additionally, assembly can be simplifiedthrough use of a single linkage 8.

The improved linear actuator 16 contains other improvements that reducetime to assemble the actuator 16. FIG. 8 is a close up view of adisassembled electric drive motor assembly 2 and rigid arm 3. The end ofthe rigid arm 3 contains one or more slots 21. The slots 21 are adaptedto receive one or more prongs 22 molded into the base of the drive motorassembly 2. The slots 21 and prongs 22 allow the drive motor assembly 2to be pressed onto the rigid arm 3 when the improved linear actuator 16is assembled. The prongs 22 apply pressure to the arm 3 to securely holdthe drive assembly 2 and rigid arm 3 together. Use of the slots 21 andprongs 22 eliminates the use of threaded fasteners to secure the driveassembly 2 and arm 3 together, decreasing manufacturing time.

FIG. 9 is a close up view of a disassembled rigid arm 3 and holder 4.The rigid arm 3 incorporates one or more fastener receiving channels 23.One or more fasteners 24 pass through one or more apertures 25 in theholder 4. In this embodiment threaded screws are used as fasteners 24,but other appropriate fasteners may be used. During assembly, the holder4 is positioned next to the rigid arm 3 so the apertures 25 in theholder 4 align with the fastener receiving channels 23 in the arm 3. Thefasteners 24 are then installed, securing the holder 4 to the rigid arm3. The use of one or more threaded screws to secure the holder 4 to thearm 3 simplifies assembly of the improved linear actuator 16 and leadsto faster production.

FIG. 10 is a perspective view of the disassembled improved linearactuator 16 with the pusher block 7 already positioned on the spindle 5.The electric drive motor assembly 2 is comprised of an electric motor26, lower assembly cover 27, and upper assembly cover 28. One or morethreaded screws 29 secure the electric motor 26 to the lower assemblycover 27 and a series of threaded screws 30 secures the upper assemblycover 28 to the lower assembly cover 27. A worm gear (not shown) isattached to the output shaft 31 of the electric motor 26. The worm gearturns a worm wheel 32 attached to the end of the threaded spindle 5. Oneend of the worm wheel 32 rests in a worm wheel bearing 33 to facilitaterotation of the spindle 5.

The spindle 5 rests within the rigid arm 3. A plastic cover 17 shieldsthe spindle 5. The spindle nut 6 is threaded onto the spindle 5 and isattached to the pusher block 7. Switches 34 are mounted within the rigidarm 3 using threaded screws 35. The switches 34 sense the position ofthe pusher block 7 and are connected to the controls (not shown) andpower source (not shown) for the improved linear actuator 16. When thepusher block 7 contacts a switch 34, power to the electric motor 26 iscut and travel of the pusher block 7 is stopped.

The holder 4 is attached to the end of the rigid arm 3 using threadedfasteners 24 that are screwed into fastener receiving channels 23 in therigid arm 3. The holder 4 may incorporate apertures 36 for receivingfasteners 37 that can be used to attach the actuator 16 to mountingpoints on the frame of a piece of adjustable furniture.

The foregoing description of preferred embodiments for the improvedlinear actuator is presented for the purposes of illustration anddescription. They are not intended to be exhaustive or to limit theinvention to the precise form disclosed. Obvious modifications orvariations are possible in light of the above teachings. The embodimentsare chosen and described in an effort to provide the best illustrationof the principles of the invention and its practical applications, andto thereby enable one of ordinary skill in the art to utilize theinvention in various embodiments and with various modifications as aresuited to the particular use contemplated.

It should be emphasized that the above-described aspects are merelypossible examples of implementations, merely set forth for a clearunderstanding of the principles of the present disclosure. Manyvariations and modifications can be made to the above-describedembodiment(s) without departing substantially from the spirit andprinciples of the present disclosure. All such modifications andvariations are intended to be included herein within the scope of thepresent disclosure, and all possible claims to individual aspects orcombinations of elements or steps are intended to be supported by thepresent disclosure. Moreover, although specific terms are employedherein, as well as in the claims that follow, they are used only in ageneric and descriptive sense, and not for the purposes of limiting thedescribed invention, nor the claims that follow.

That which is claimed:
 1. An arm assembly for a linear actuator foradjustable furniture, the arm assembly comprising: a rigid arm; athreaded spindle extending along a threaded spindle axis; and a pusherblock comprising: a pusher block body comprising: a rigid arm passage,wherein the rigid arm extends through the rigid arm passage such thatthe pusher block is movable along the rigid arm; and a spindle passagevertically offset, and physically separated, from the rigid arm passage,wherein the threaded spindle extends through the spindle passage; andtwo attachment arms extending from the pusher block body, the attachmentarms defining a linkage channel therebetween and at least one securingaperture, wherein the at least one securing aperture extends along asecuring aperture axis, wherein the securing aperture axis extendstransversely to the threaded spindle axis and is vertically offset fromthe threaded spindle axis such that the securing aperture axis does notintersect the threaded spindle axis, and wherein the linkage channel isconfigured to receive an end of a linkage.
 2. The arm assembly of claim1, further comprising: the linkage comprising the end, wherein thelinkage is pivotally connected to the pusher block at a position that isvertically offset from the threaded spindle axis; and a drive assemblyconfigured to rotate the threaded spindle such that the pusher blockmoves along the rigid arm.
 3. The arm assembly of claim 1, wherein thepusher block body comprises a top surface and at least one side surfaceextending downwardly from the top surface and wherein each of the twoattachment arms extends from at least one of the top surface and the atleast one side surface of the pusher block body.
 4. The arm assembly ofclaim 1, further comprising a single fastener removably positionedwithin the at least one securing aperture and configured to engage theend of the linkage to pivotally connect the linkage to the pusher block.5. The arm assembly of claim 4, wherein the at least one securingaperture comprises two securing apertures, each extending along thesecuring aperture axis and wherein the single fastener extends throughthe two securing apertures.
 6. The arm assembly of claim 1, wherein thesecuring aperture axis is vertically offset above the threaded spindleaxis.
 7. The arm assembly of claim 1, wherein the pusher block body andthe two attachment arms are formed integrally.
 8. An arm assembly for alinear actuator for adjustable furniture, the arm assembly comprising: arigid arm; a threaded spindle extending along a threaded spindle axis; apusher block comprising: a pusher block body comprising: a rigid armpassage, wherein the rigid arm extends through the rigid arm passagesuch that the pusher block is movable along the rigid arm; and a spindlepassage vertically offset, and physically separated, from the rigid armpassage, wherein the threaded spindle extends through the spindlepassage; and two attachment arms extending from the pusher block body,the attachment arms defining a linkage channel therebetween and twosecuring apertures extending along a securing aperture axis, wherein thesecuring aperture axis extends transversely to the threaded spindle axisand is vertically offset from the threaded spindle axis such that thesecuring aperture axis and the threaded spindle axis do not intersect;and a single fastener extending through the two securing apertures andconfigured to engage an end of a linkage such that the end of thelinkage is pivotally connected to the pusher block solely through thesingle fastener and such that a connection between the end of thelinkage and the pusher block is vertically offset from the threadedspindle axis.
 9. The arm assembly of claim 8, wherein the pusher blockbody and the two attachment arms are formed integrally.
 10. The armassembly of claim 8, further comprising: the linkage, wherein thelinkage is configured to attach to a piece of adjustable furniture andcomprises a first end and a second end, wherein the single fastenerextends through the first end such that the linkage is pivotallyconnected to the pusher block solely through the single fastener; and adrive assembly configured to rotate the threaded spindle such that thepusher block moves along the rigid arm.
 11. The linear actuator of claim8, wherein the single fastener is a clevis pin.
 12. The arm assembly ofclaim 8, wherein the pusher block body and the two attachment arms areformed integrally.
 13. A pusher block for an arm assembly for a linearactuator for adjustable furniture, the pusher block comprising: a pusherblock body comprising: a first end; a second end opposite the first end;a rigid arm passage extending through the pusher block body from thefirst end to the second end, wherein the rigid arm passage is configuredto receive a rigid arm of the linear actuator through the rigid armpassage such that the pusher block is slidable along the rigid arm; anda spindle passage extending through the pusher block body from the firstend to the second end, wherein the spindle passage extends along aspindle axis and is configured to receive a spindle of the linearactuator, and wherein the spindle passage is vertically offset andphysically separated from the rigid arm passage; two attachment armsextending from the pusher block body and defining at least one securingaperture extending along a securing aperture axis, wherein the securingaperture axis extends transversely to the spindle axis and is verticallyoffset from the spindle axis such that the securing aperture axis andthe spindle axis do not intersect; and a fastener removably positionedwithin the at least one securing aperture, wherein the fastener isconfigured to pivotally connect the pusher block with a first end of alinkage.
 14. The pusher block of claim 13, wherein the pusher block bodyand the two attachment arms are formed integrally.
 15. The pusher blockof claim 13, wherein the at least one securing aperture comprises twosecuring apertures, each extending along the securing aperture axis, andwherein the fastener comprises a single fastener positioned within thetwo securing apertures.
 16. An arm assembly for a linear actuator foradjustable furniture, the arm assembly comprising: a rigid arm; athreaded spindle extending along a threaded spindle axis; a pusher blockcomprising: a pusher block body comprising: a spindle nut threadablyengaged with the threaded spindle; and a rigid arm passage, wherein therigid arm extends through the rigid arm passage such that the pusherblock body is slidable along the rigid arm; and two attachment armsextending from the pusher block body and defining a linkage channel anda securing aperture, wherein the securing aperture extends transverselyto the linkage channel and is in communication with the linkage channel,wherein the securing aperture extends along a securing aperture axis,wherein the securing aperture axis is vertically offset from thethreaded spindle axis, and wherein the linkage channel is configured toreceive an end of a linkage within the linkage channel.
 17. The armassembly of claim 16, wherein an outer surface of the pusher block bodycomprises a top surface and at least one side surface extendingdownwardly from the top surface, and wherein the two attachment armsextend outwardly from at least one of the top surface and the at leastone side surface of the pusher block body.
 18. The arm assembly of claim16, wherein the pusher block body and the two attachment arms are formedintegrally.
 19. The arm assembly of claim 16, further comprising: thelinkage, wherein the linkage is configured to attach to a piece ofadjustable furniture; and a fastener removably positioned within thesecuring aperture, wherein the fastener is configured to engage with theend of the linkage within the linkage channel.
 20. The arm assembly ofclaim 16, wherein the spindle nut defines a spindle passage in thepusher block body that is vertically offset and physically separatedfrom the rigid arm passage of the pusher block body, and wherein thethreaded spindle is received within the spindle passage.